Since u have 4 Gig of ram like me, ram usage is never >27%(atleast for me ). U can avoid pagefile .. it hugely effects system performance .. plus u can c immediate effect in games like COD:MW2 .. ( i can run games on higer settig now , trust me). Not only games .. application once opened up response really fast and also they open up real reallly quick.
The only down side is , when ur memory is 75-80% used games like crysis and crysis warhead will tell u that u r low on memory and will exit after about 20-30 mins of gameplay . THIS IS SHIT consdering the remaning 20% is about 800mb ram.
There is no way around this so u have to keep page file if u wanna play those games. But this just happene to me while playing crysis, never again.
SO conclusion - try not to keep the page file.
If u wanna keep the page file then set it to 1024-1024. Not maintened by widows. THis way it wont cause fragmentation problems !!!